It is oftentimes necessary, or at least desirable, to synchronize operation of two or more devices. One area in which considerable development has heretofore taken place has been in synchronizing sound with motion pictures. For the commercial, or professional, motion picture industry, systems have been developed for achieving such synchronization, but such systems have not proved to be economically feasible and/or practical for amateur use with smaller size film.
For amateur use, various systems have been suggested and/or utilized for synchronizing sound and picture. Included in such suggested systems have been systems for synchronizing movie cameras and/or projectors with tape recorders. Among such systems has been a unit offering a common drive for a projector and tape recorder, systems with various switch actuations in one unit controlling operation of the second unit, systems for recording of signals on tape for timing purposes, and systems for sensing a lack of synchronization between picture and sound. Also such systems have utilized sensors such as vibration and induction coil pick-ups, and utilized the produced signals for synchronization purposes. Examples of such systems may be found, for example, in U.S. Pat. Nos. 2,679,187 and 3,743,392.
While such systems have proved to be satisfactory, at least for some purposes, none of these systems have proved to be completely suitable beyond improvement in providing a synchronizing system for synchronizing motion picture and sound recordings that is practical for use by amateurs. Improvement in such a system has therefore been needed.